Process of brewing beer.



L. NATHANst H. BoLzE,

PROCESS 0I' BREWING EBB. `APPLxoATIoN FILED JUNE 1, 1901.

899,756.` Patented sept. 29, 190s.

Pun? I :s- @fi @WA/mam BOLZE, of Mannheim, in the-Grand'Duchy of,

ess by which the time re uircd to. produce 55 Thepipe, E, also has anothei connection,

- fluence of contact with metal. The cover has I To` all whom tt may concern:

`lager bee ,carbonio acid, the features which distinguish UNITED STATES PATENT oEEroE.

LEoPoLD NATHAN, or ZURICH, SWITZERLAND, AND EANs BoLzE, or MANN-HEIM, GERMANY,

, sAID BoD-"ZE AssIGNoR To sAID NATHAN,

PEocEss F BREWINGl BEER.

Specification of Letters Patent. i Application led June 1, 1901.. Serial No. l62,782.

Patented sept. 29, 1908.

Be it known that we, LEoPoLD NATHAN, chemist, of Zurich, Switzerland, and HANS Baden, Germany, have invented new and useful -Improvements in Processes of Brewing Beer, of which the following is a specification.

Our invention relates tothe art ofbrewing beer, and has for its object to Aprovide a procwell-keeping and markctab e beer,`is considerably reduced, bv whichthenoxious influ-v ence of undesirable bacteria is avoided, and in which the fermentation can be controlled with certainty so as to vary the qualities of the beer produced and to give it the taste of -The invention consists-in a particular novel treatment `which involves cooling, stirring, aeration, fermentation, and treatment With our invention from the prior state of the'art being pointed out in the appended claims, while an example of the entire treatment is described in detail in the statement following hereinafter. Y

An apparatus suitable for the purposes of ourinvention is shown in the accompanying drawing, in which 4 Y Figure 1 is a sectional elevation of theap` paratus, and'Fig. 2 isa top view of the stirrer which forms 'part of the apparatus.

The vessel A has .a cover B for closing it hermetically, and the inner walls should be devoid ofl rojections to facilitate cleaning,. and shoulbe enameled so as to-protect the wort and the beer against the injurious ina stufHng box band a. bracket 'B' in which is jouraled the vertical shaft C driven by bevel gearing c and carrying at its lower end .'the spindle D providedwith the stirrer d; the jlat# ter as shown consists of fourblades or wings inclined relatively to the axis of rotation. At Y the bottom of the receptacle A is located a supply i e E, and thevessel A is further surrounded liy a'j acket F through which a heating medium or a cooling medium may be circu ated.v The -supply pi e E is connected with the surrounding air t rough the medium of air filter G of any suitable construction (a 'box `illed with cotton 'batting will do) the connection beingi controlled lby a valve g.

`with i the upper tion.

controlled by a valve h and leading to a ves sel H adapted to containv the yeast used for producing fermentation. The air or the yeast may be\conveyed through the supply pipe E either by pressure, or by suction, as y means of a vacuum pump I connected part of the vessel A or with the cover B thereof.

The process of brewing beer according to our invention is as follows: A Wort is prepared in." any lapproved manner, our inventlon having no reference t'o the roduction of the wort. This wort is, Whi e hot, introduced into the cooling and fermenting vessel l A, through the jacket F of which a cooling agent (such as brine) is circulated. We thus dlspense with a separate cooler. l The stirrer d is rotatedso as to cause the Wort to be thrown out a ainst the cooledwalls and to then How bac toward the spindle D, thus keeping the entire -body of Wort agitated and hastenlng the cooling action. As a rule, .the

Wort is ,cooled to jaA temperature offrom 7 to 10 centigrade, this temperature being some- -What higher than-1 that usually' employed. We are enabled-to' lstop the cooling earlier than ordinarilypracticed, for thereason that great careisftaken to exclude, all undesirable germs. This is secured partly/by enameling the surfaceswith Which the wort comes in contact, and partly by keeping the vessel hermetically tight and sterilizing the air Which is admitted during the cooling opera- This air passes through the filter G and supply pipe E, beingsucked in by the pump l, 1t being understood that at this time `the valve 'g is open and the valve h is closed.

The Wort absorbs the air thusintroduced, and the saturation with air is promoted by the agitation effected'by the stirrer d. The

wort receives a whirling motion, so that it assumes the shape'of afunnel, and thus cooling and aerationlare effectively carried out at the same time.

When the wort has been cooled to the temperature hereinbefore indicated, we introduce Into. it pure culture yeast from the vessel H,

by the action of the pump 1;: the valveh now being opened, while the valve-g mafbe closed. The preparation or" culture o the 'yeast prior to its introduction vinto the Wort may be done inA any'approved manner and forms no pant of our present invention The yeast should preferably be in a' viscous ,or semi-liquid state, so that it maybe conveyed rotation (160 revolutions a minute, more or less), and this is kept up for about two hours.-

The circulation and whirling of the wort causes a most minute and uniform subdivision of all solid and gaseous substances contained inthe liquid. Not only is there a thorough agitation of the air which has been introduced during the` cooling and .which may still be introduced during this second ste (the fermentation) or during part thereof, ut the yeast which may have a tendency to rise to the surface is forced downward at the center of the vessel. 0f course the subdivision of the yeast and its uniform distribution within the wort accelerate the fermentation, as a very large active surface is obtained for'the yeast. #The energetic stirring/also has a beneficial iniiuence on the growth of the yeast. It is well--known that the development of yeast takes place by the budding or formation of new cellsat the sides of the original cells, the new cells growingby degrees while still in connection with the original cells, and also becoming linked or connected with other cells. The rapidly rotating stirrer weemploy separates the new cells from the old ones as soon as the former have attained a certain growth, and thus thev .new cells areisolated to lform new foci of growth, it havin been found that single cells generate newce s more rapidly and abu'ndantly 'than cells which have remained Vconl nected with the original cells. The advisability of continuing the introduction of air during the fermentation is determined by the amount of air previously introduced .and by the quality of theyeast; that is, if the yeast used is capable of satisfactory development in the aerated wort, such as the said wort is at the end ofthe cooling of the wort, it will i" cells will begin to grow in a feo not be necessary .to continue the aeration during the fermentation. Any experienced brewer can tellfrom the appearance of the yeast whether or not it it is in proper condition for further development, and if it isin such (condition at the end of the cooling operation, aeration during fermentation ,will

not be necessary. The violent agitation ofv the yeast by the stirrer rotating at a comparatively high speed continuously br aks up the yeast cells and prevents them om p J growing beyond. a certain size, and therefore eeps t em of a uniform relatively small size;

.when this violent agitation is stopped, the

llrlactically uniform manner and will get ked` to each other untilthe full growth has been attained. When the attendant asee'rtains that there is no further growth, he knows that it is time to -again violently agitate the liquid. We

I, have found that.violentl agitation which isolates the yeast cells makes such cells much more active than if they are lallowed to grow undisturbed all the time. The strong stirring is continued for about two hours, as above stated, and then is arrested for three or four hours. During this period of rest, the cells are allowed to growundisturbed and form alcohol in the usual manner. The wort should be kept cool during fermentation,

`about 10 centigrade being a suitable temperature.

i The carbonio acid which is generated durlng the fermentation is recovered for further use. The period of rest (three or four hours) should be followed by another period. of strong agitation (about two hours), and it is 'best to begin the new 'stirring action when nately agitated violently (for about two hours) and thenallowed to remain at rest] (for about three or four hours), so. as to separate the yeast cells from each other and distribute them within the wort, and then again to allow new cells'to grow to full size, with the concurrent formation of alcohol and carbonio acid'. These periods of agitation and rest should succeed each otherwithout intermission for two or three d ays as stated. The introduction of air, which may take place (preferably-periodically) during this fermentation, serves not only to promote ythedevelopment of the yeast by supplying more oxygen thereto, but asthe air passes through the wort, and leaves the receptacle A, said air carries with it volatile substances which form the raw and immature bouquet of fermrltation, or at least part of these substances. v

The violent fermentation produced as above described by'alternate periods of agitation and rest, should be continued until the beer attains about three-fourths of the intended alcoholic strength. The existence of this condition might be ascertained by a direct test of alcoholic strength or indirectly by the appearance or amount of the yeast developed. In practice the latter indirect metho is employed on account of its greater simplicity since it requires nothing but ocular observation. Any experienced brewer can tell the condition of the yeast by its appearance. ,Aeration should in any event be discontinuedafter the violent. fermentation, otherwise the beer would acquire a flat taste. v'

` When the beer has attained about threefourths of the desired alcoholic strength, a period of rest of about twelve hours is alowed to elapse, during which the vold cells immature bouquets formed during fermenta- 'will mature, imparting tothe beer its old `or matured fiavor.

These cells being in a state of fine subdivision will-settle slowly'.

After this period of rest, the stirrer is again' During the comparatively long period of i rest (twelve hours) and the agitation which follow the violent fermentation, carbonio acid is passed through the beer. This carbonic acid takes up, and carries away the tion, without giving a fiat' taste to the beer,

= and is also partly absorbed by the beer.

The carbonio acid may be treated in any suitable way after its passage through the beer, in order to remove the raw bouquet from the acid, and the acid thus purified may be sent again through the liquid-.to take up another proportion of the immature bouquet. The carbonicacid formed during fermentation may be stored and added-.tou

the beer. The passage. of carbonio acid through the wort or beer as distinguished from the mere introduction and absorption of carbonio acid, is of great importance, as it removes the raw bouquet without impairing the flavor of the beer. -During the occurrence of the break and the precipitation of the yeast, the temperature (which, as stated, should be about'lOo centigrade during the fermentation) rises a` few -degrees. This promotes the separation of the yeast. The beer is drawn ,off into another vessel, so as to separateit from'the precipitated. yeast, The beer thus produced only needs clarification'to convert it into a readily marketable product. It need not) be stored for a certain length of time, but has at the end of the entire process, which lasts about four or five days, the flavor and taste'. of well-matured been Further, the beer thus producedv kee s exceedingly well. If it is desired to furt 1er improve the keeping quality of the beer, it may be pasteurized, in which case a lower degree of heat will suffice than is ordinarily required, on account of the' absence of any germs except the yeast. The beer isvfinally impregnated with carbonic acid. I

We desire it to be clearly understood that the attendant will-have to be guided by the alppearance of the wort andbeer, as well as by t e taste thereof, in determining the proper f time for beginning land ending the various sire to secure by Letters-Patent, is

steps of the process hereinbefore described.

Thev specific periods oftime named inthisA description may therefore be varied considerably without departing from the nature of our invention. While we have described the use of carbonio acid for the purpose of removing the raw bouquet, we desire it to be under- .Y

stood that any other indifferent gas may be employed, that is, any gas which does -not injuriously affect the beer, and the claims in which carbonio acid is mentioned in this conn'ection are to be interpreted as covering other indifferent gases as equivalents.

What we claim as our invention, and de- 1. In the brewingof beer,.theA improvement which consists in stirring and aerating the wort and simultaneously cooling it, then introducing yeast andl giving the wort, during the ensuing fermentation, alternate .Q

periods of agitation and rest, until about three-fourths of the strength has been produced, then giving. the beer a further period of rest and passing car-y bonio lacid through it during such period,"

.Irioderately stirring the ber to-cause a precipit-ation of the yeast, and finally separating the beer from the yeast.

intended alcoholic 2. In t-he art of l'brewing beer, the improvement in t'he fermentation of the wort which 9 consists in introducing yeast into the wort vand giving the'latter, during the ensuing fermentation, alternate eriods of strong agitation and of rest, unti about three-fourths of the intended alcoholic strength hasbeen produced, then giving the beer a further. period of rest and passing carbonio acid through it during-such period, moderately stirring the beer to cause a precipitation 'of the yeast, and finally separating the beer from the yeast.

3. In the art of brewing beer, the improve- A merit in the fermentation ofthe wort which consists in introducing yeast into the wort 4 and giving the latter, during the ensuing fermentation, 'alternate -periods of agitation and rest, .and terminating this procedure bement inthe fermentation of the Wort which consists in passing carbonio acid through the wort lafter'the main fermentation, and then separating Vthe yeast from the beer.

5f In the art of brewing beer, the improvement in the fermentation of the wort which `consists in subecting the wort first toviolent and then to re atively slow fermentation and passing carbonio acid through the wort dur,- lng the slow fermentation.

6. Inthe artlof brewing beer, the improvef ment in the fermentation of the wort which consists in subjecting the wort first to violent and then to relativelyslow fermentation, aerating the wort during the violent fermentation, and passing carbonic acid through the wort during the slow fermentation.

7. In the art of brewing beer, the improvement in the fermentation of the wort which consists in subjecting the wort first to violent fermentation until about three-fourths of the intended alcoholic strength is obtained, and then to relatively slow fermentation. f' 8. In the. art of brewing beer, the improvement which consists in fermenting the Wort, and then passing a current of carbonio acidI through the Wort during a considerable length of time, so that carbonio acid enters into the wort and at the same time carbonic acid,

laden with the immature bouquets which it has taken up from the liquid leaves the wort. .9. The herein described improvement in the arglof manufacturing beverages, con- Nathan:

the same periodically; and at the end of the,

violent fermentation thus produced, the ripening of the product by t 1e injection of CO2, all yin one continuous operation in a single closed vessel.

ln testimony whereof, we have slgned our `names to this specification, in the presence of two subscribing witnesses.

LEOPOLD NATHAN. HANS BOLZE.

iVVitnesses as to the signature of Leopold A. LIEBERKNECHT, H.-GUERIN DE WALn ERBACII.

Witnesses as to the signature of Hans Bolze:

QscAR Boon, FRrTi ULLMANN. 

